Combined Targeting of the Glutathione and Thioredoxin Antioxidant Systems in Pancreatic Cancer

Pancreatic ductal adenocarcinoma is characterized by increased generation of reactive oxygen species that can cause lethal oxidative stress. Here, we evaluated the combined inhibition of the glutathione and thioredoxin antioxidant systems in preclinical models of pancreatic ductal adenocarcinoma, using buthionine sulfoximine (BSO) that targets glutathione synthesis, and auranofin that targets thioredoxin recycling. BSO potentiated the cytotoxicity of auranofin and induced lethal oxidative stress in primary pancreatic cancer cells. As assessed by the cellular thermal shift assay, auranofin engaged with thioredoxin reductase 1 in primary cells at concentrations known to induce cell death. Moreover, we used imaging mass cytometry to map the biodistribution of atomic gold in patient-derived xenografts treated with auranofin, and the drug was readily detectable throughout the epithelial and stromal compartments after treatment with a clinically relevant dose. In conclusion, combinatorial treatment with BSO and auranofin could serve as a potential therapeutic strategy in pancreatic ductal adenocarcinoma.

An Iodinated DAPI-Based Reagent for Mass Cytometry

Multiparametric single-cell analysis has seen dramatic improvements with the introduction of mass cytometry (MC) and imaging mass cytometry (IMC^™ ). These technologies expanded the number of biomarkers that can be identified simultaneously by using heavy-isotope-tagged antibody reagents. Small-molecule probes bearing heavy isotopes are emerging as additional useful functional reporters of cellular features. Realizing this, we explored the iodination of DAPI to produce a heavy-atom-substituted derivative of the commonly used fluorescent DNA stain. Although exhibiting a drastically reduced fluorescence emission profile, I-DAPI retains strong binding affinity for DNA. I-DAPI was used to detect cellular DNA in MC and IMC™ assays with comparable efficiency to known Ir-containing DNA intercalators. This work suggests repurposing well-known colorimetric stains through simple reactions could be an effective strategy to develop new, functional MC and IMC™ reagents.

Guidelines for the use of flow cytometry and cell sorting in immunological studies (second edition)

These guidelines are a consensus work of a considerable number of members of the immunology and flow cytometry community. They provide the theory and key practical aspects of flow cytometry enabling immunologists to avoid the common errors that often undermine immunological data. Notably, there are comprehensive sections of all major immune cell types with helpful Tables detailing phenotypes in murine and human cells. The latest flow cytometry techniques and applications are also described, featuring examples of the data that can be generated and, importantly, how the data can be analysed. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid, all written and peer-reviewed by leading experts in the field, making this an essential research companion.

Development of ICSI

The first conception outside of the human body that led to the birth of Louise Brown was a tremendous accomplishment, which opened the door to the utilization of assisted reproductive techniques globally. This brought the understanding that accomplishing life in a dish required several steps, the most obvious being the timing and characteristics of fertilization. It soon became obvious in the 1980s that the most disappointing phenomenon was unexpected and complete fertilization failure. Among the approaches that were attempted to treat male factor infertility, ICSI surfaced as the technique that brought the ratio of the gametes to 1:1 and was also able to grant consistent fertilization and a higher pregnancy rate. ICSI has now been implemented for a quarter of a century, proving itself as the ultimate technique utilizing ejaculated spermatozoa independent of the semen parameters and is the sole insemination method to be used with surgically retrieved spermatozoa. There are currently various indications for ICSI that are widely adopted, rendering it the most popular insemination method worldwide. The reliability of ICSI ensures its employment in upcoming techniques involving in vitro spermatogenesis and neogametogenesis.

Intracytoplasmic sperm injection: state of the art in humans

Among infertile couples, 25% involve both male and female factors, while male factor alone accounts for another 25% due to oligo-, astheno-, teratozoospermia, a combination of the three, or even a complete absence of sperm cells in the ejaculate and can lead to a poor prognosis even with the help of assisted reproductive technology (ART). Intracytoplasmic sperm injection (ICSI) has been with us now for a quarter of a century and in spite of the controversy generated since its inception, it remains in the forefront of the techniques utilized in ART. The development of ICSI in 1992 has drastically decreased the impact of male factor, resulting in millions of pregnancies worldwide for couples who, without ICSI, would have had little chance of having their own biological child. This review focuses on the state of the art of ICSI regarding utility of bioassays that evaluate male factor infertility beyond the standard semen analysis and describes the current application and advances in regard to ICSI, particularly the genetic and epigenetic characteristics of spermatozoa and their impact on reproductive outcome.

Reproductive isolation between sympatric Anguilla japonica and Anguilla marmorata

Species-specific restriction fragment length polymorphism in the intron of the androgen receptor gene (ar5) was found in glass to silver-stage individuals of Anguilla japonica (n = 51) and A. marmorata (n = 21). The sequence analysis of 16S rDNA from 328 anguillid leptocephali collected in the North Equatorial Current of the western North Pacific Ocean revealed the specimens to be A. japonica (n = 194), A. marmorata (n = 128), A. bicolor pacifica (n = 5) and A. luzonensis (n = 1). All leptocephali of A. japonica and A. marmorata were monomorphic and did not share an allele at the ar5 locus, indicating that the two species are reproductively isolated.

High-dose interleukin2 - a 10-year single-site experience in the treatment of metastatic renal cell carcinoma: careful selection of patients gives an excellent outcome

Background

VEGF-targeted therapy has become the mainstay of treatment for majority of mRCC patients. For most patients, benefit is short-lived and therefore treatment remains palliative in intent. HD IL2 is an effective immunotherapy treatment capable of durable remission in some patients but its unselected use has been difficult due to its modest response rate and considerable adverse effects. Using set pathology criteria as a selection tool in clinical practice, we have been able to show improved outcomes in our previous report. Here, we present an updated and extended report of this treatment and seek to explore any pathological, clinical and treatment variables likely to predict better outcomes.

Methods

This is an extension of a previously reported clinical audit, which includes mRCC cases treated with HD IL2 between 2003 and 2013. Since 2006, tumour specimens of potential candidates were routinely reviewed prospectively and stratified into Favourable or Other categories based on constitution of histological growth pattern, namely alveolar or solid versus papillary and/or sarcomatoid architecture; clear cell versus granular cell cytoplasmic morphology. HD IL2 was preferentially offered to patients with Favourable pathology. Outcome evaluation includes response rates, survival, and treatment tolerance. Multivariate analysis was performed to explore potential prognostic and predictive factors.

Results

Among prospectively selected patients with Favourable pathology (n = 106), overall response rate was 48.1 % (51/106) with CR rate of 21.6 % (23/106). Median OS was 58.1 months. Factors associated with significantly better response and/or survival includes favourable pathology pattern, higher cycle 1 tolerance and lower number of metastatic organ sites (<3). CAIX (Carbonic anhydrase 9) has prognostic value but is not predictive of response. Toxicities were those expected of IL2 but were manageable on general medical wards, with no treatment-related death. Importantly most complete responses were durable with 76 % (23/30) cases remained relapse-free (median 39 months follow up) and 2 of the seven who relapsed had had long-term disease free survival after resection of oligometastatic relapse.

Conclusions

Our experience shows that HD IL2 remains an effective and safe treatment in well-selected cases of mRCC. The result in this single-institution patient series confirms similar outcomes to our previously reported retrospective series. Given the prospect of long-term remission, fit patients with Favourable histology and low disease burden should be considered for HD IL2 in an experienced centre. Better understanding has been gained from this in-depth analysis especially the examination of possible response predictors and strategies that can improve treatment outcome.

Electronic supplementary material

The online version of this article (doi:10.1186/s40425-016-0174-5) contains supplementary material, which is available to authorized users.

A giant anguilliform leptocephalus Thalassenchelys foliaceus Castle & Raju is a junior synonym of Congriscus maldivensis (Norman 1939)

A single specimen of giant leptocephalus Thalassenchelys foliaceus Castle & Raju 1975 was caught in subtropical waters of the western North Pacific Ocean. Mitochondrial coI gene sequence divergence between T. foliaceus and Congriscus maldivensis (Norman 1939) was 0·64 ± 0·27% (mean ± s.e.), and the myomere and vertebral counts of these species were similar, indicating T. foliaceus is a junior synonym of C. maldivensis.

A phase I trial of the aurora kinase inhibitor, ENMD-2076, in patients with relapsed or refractory acute myeloid leukemia or chronic myelomonocytic leukemia

ENMD-2076 is a novel, orally-active molecule that inhibits Aurora A kinase, as well as c-Kit, FLT3 and VEGFR2. A phase I study was conducted to determine the maximum tolerated dose (MTD), recommended phase 2 dose (RP2D) and toxicities of ENMD-2076 in patients with acute myeloid leukemia (AML) and chronic myelomonocytic leukemia (CMML). Patients received escalating doses of ENMD-2076 administered orally daily [225 mg (n = 7), 375 mg (n = 6), 325 mg (n = 9), or 275 mg (n = 5)]. Twenty-seven patients were treated (26 AML; 1 CMML-2). The most common non-hematological toxicities of any grade, regardless of association with drug, were fatigue, diarrhea, dysphonia, dyspnea, hypertension, constipation, and abdominal pain. Dose-limiting toxicities (DLTs) consisted of grade 3 fatigue, grade 3 typhilitis, grade 3 syncope and grade 3 QTc prolongation). Of the 16 evaluable patients, one patient achieved a complete remission with incomplete count recovery (CRi), three experienced a morphologic leukemia-free state (MLFS) with a major hematologic improvement in platelets (HI-P), and 5 other patients had a reduction in marrow blast percentage (i.e. 11-65 %). The RP2D in this patient population is 225 mg orally once daily.

Abstract A204: Flow cytometric assay of proteasome inhibition in whole blood

Introduction: Two proteasome inhibitors are currently approved by the US FDA for the treatment of multiple myeloma: bortezomib and carfilzomib. Both drugs make a covalent bond with a Thr in the active site of the 20S catalytic β5 subunit. While the covalent bond is hydrolyzable in the case of bortezomib, its binding is characterized by a long residency time with a half-life of close to 2 hours. The current clinical surrogate assay measures the suppression of proteasome activity in pooled cell lysates from patients’ blood or tissue following the administration of inhibitor. As such, this assay depends upon the long residency time of current inhibitors. Second-generation proteasome inhibitors that are in development, such as ixazomib, have a much faster off-rate, making accurate measurement of inhibition in diluted cell lysates problematic. Our objective was to develop a surrogate proteasome assay for use in whole blood, without requiring cell lysis, thus preventing sample dilution.

Methods: Whole-blood samples were pre-incubated with proteasome inhibitors for 1-2 hours at 37°C. Subsequently, samples were stimulated with LPS at 37°C, then fixed and permeabilized using PerFix-P (Beckman Coulter). Washed white blood cells were stained with IκBα-AF488 (Cell Signaling Technologies), CD45-KrO, and CD14-PC7 monoclonal antibodies (Beckman Coulter) and analyzed using a Gallios™ flow cytometer.

Results and Discussion: During the classical activation of NF-κB signaling, the NF-κB inhibitor, IκBα, undergoes phosphorylation and ubiquitination, followed by rapid proteasomal degradation. Released NF-κB complexes can then translocate to the nucleus, where they initiate transcriptional activation. In this study, we analyzed the LPS-induced degradation of IκBα in whole-blood monocytes by flow cytometry. We found a 70-80% decrease in the median fluorescent intensity (MFI) of IκBα-AF488 after 10 min of LPS stimulation. The kinetic profile and magnitude of the MFI reduction were highly reproducible in whole-blood monocytes from healthy donors, as well as in a limited number of blood samples obtained from multiple-myeloma patients. The MFI reduction was inhibited in a dose-dependent manner by different proteasome inhibitors, including bortezomib, carfilzomib, and MG132. To increase the specificity of the assay, ERK phosphorylation can also be monitored simultaneously within the same cells. ERK phosphorylation in whole-blood monocytes peaks at ∼10 min after LPS stimulation, and is caused by the release of TPL2 from its complex with p105 (unprocessed NF-κB1) following the proteasomal processing of p105 into p50. Because of this, ERK phosphorylation is also inhibited by proteasome inhibitors in a dose-dependent manner, similar to IκBα. This assay can be optimized for different cell types within whole blood by using different activators, although the kinetics of IκBα degradation varies.

Conclusions: We have established a fast and convenient assay to measure proteasome activity and inhibition in whole blood leukocytes. This assay can be used for investigation of the PK/PD relationships of new-generation proteasome inhibitors with fast off-rates.

Disclaimer: PerFix-P and Gallios™ are for research use only. Not for use in diagnostic procedures.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A204.

Citation Format: Sergei Gulnik, T. Vincent Shankey, Lidice L. Lopez, David W. Hedley, Sue Chow. Flow cytometric assay of proteasome inhibition in whole blood. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A204.

Abstract 4647: Tie2-expressing monocytes (TEMs) as potential biomarkers of angiopoietin-Tie2 (Ang/Tie2) directed therapies: correlative analysis of a phase I study of AMG386 + temsirolimus (T)

Background: The Ang/Tie2 pathway plays a critical role in tumor angiogenesis, and several agents targeting this axis are in development. Tie2 is expressed by monocytes (M), and TEMs may be angiogenic mediators. Thymidine phosphorylase (TP), an angiogenic enzyme, is increased in TEMs upon Tie2 stimulation. We used flow cytometry to evaluate TEMs in a phase I study of AMG386 (Ang1/2 peptibody) + T in patients (pts) with solid tumors.

Methods: Peripheral blood was collected from healthy volunteers and pts with advanced cancer (n=10 each) for assay development. For phase I study pts (n=5 to date), blood was collected on Cycle 1 Day 1 (D1), D3 and D8. Extracellular Tie2 staining was performed after hypotonic red blood cell lysis. TP staining followed formaldehyde fixation and Triton X-100 permeabilization. M and lymphocytes (L) were gated with CD45 and CD33. Median fluorescence intensities (MFI) were measured and normalized by calculating a M/L ratio. Tumor response was assessed every 2 cycles.

Results: Tie2 staining was present on all M (absent in other leukocytes) in healthy controls and cancer pts, with no discrete Tie2+/- populations. Tie2 and TP M/L were similar between these 2 groups. Tie2, TP and response data from the first 5 pts receiving AMG386 + T are presented. Preliminary results reveal an association between change in TP D1 to D3 and tumor response. TP M/L decreased in all pts with tumor shrinkage (mean -18%), but increased (+6%) in the pt with tumor growth. No consistent association between Tie2 M/L and response was observed.

Conclusions: Measurement of Tie2 and TP in circulating M is feasible. No discrete Tie2+ M population is identifiable. Tie2 and TP staining are similar in cancer pts and healthy volunteers. Preliminary analyses reveal an association between an initial reduction in TP and tumor shrinkage in pts receiving AMG386+T. Enrolment continues and additional data will be presented.

Tie2, TP and tumor response in the first 5 pts receiving AMG386+T Patient 1 2 3 4 5 Tie2 M/L D1 2.63 2.53 6.56 5.07 9.85 D3 2.58 2.41 6.07 4.94 13.87 D8 3.33 2.61 5.11 7.85 7.95 Tie2% Change D1 to D3 −2.1% -4.9% -7.5% -2.5% 40.7% TP M/L D1 7.41 5.49 8.98 6.59 5.43 D3 6.70 5.83 8.11 5.21 3.81 D8 11.07 9.21 9.19 5.70 5.63 TP% Change D1 to D3 -9.6% 6.2% -9.6% -20.8% -30.0% Best response in target lesions (% change) -25% 14% -31% -14% -7% This study is supported by the National Cancer Institute Grant # U01-CA-132123

Citation Format: David W. Cescon, Philippe L. Bedard, Sue Chow, Helen Chen, Albiruni Razak, Monika Wizemann, Lillian L. Siu, David Hedley. Tie2-expressing monocytes (TEMs) as potential biomarkers of angiopoietin-Tie2 (Ang/Tie2) directed therapies: correlative analysis of a phase I study of AMG386 + temsirolimus (T). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4647. doi:10.1158/1538-7445.AM2013-4647

Glycogen synthase kinase-3 inhibition sensitizes pancreatic cancer cells to TRAIL-induced apoptosis

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) induces apoptosis in a variety of cancer cell lines with little or no effect on normal cells. However, its effect is limited as some cancers including pancreatic cancer show de novo resistance to TRAIL induced apoptosis. In this study we report that GSK-3 inhibition using the pharmacologic agent AR-18, enhanced TRAIL sensitivity in a range of pancreatic and prostate cancer cell lines. This sensitization was found to be caspase-dependent, and both pharmacological and genetic knock-down of GSK-3 isoforms resulted in apoptotic features as shown by cleavage of PARP and caspase-3. Elevated levels of reactive oxygen intermediates and disturbance of mitochondrial membrane potential point to a mitochondrial amplification loop for TRAIL-induced apoptosis after GSK-3 inhibition. Consistent with this, overexpression of anti-apoptotic mitochondrial targets such as Bcl-XL, Mcl-1, and Bcl-2 rescued PANC-1 and PPC-1 cells from TRAIL sensitization. However, overexpression of the caspase-8 inhibitor CrmA also inhibited the sensitizing effects of GSK-3 inhibitor, suggesting an additional role for GSK-3 that inhibits death receptor signaling. Acute treatment of mice bearing PANC-1 xenografts with a combination of AR-18 and TRAIL also resulted in a significant increase in apoptosis, as measured by caspase-3 cleavage. Sensitization to TRAIL occurred despite an increase in β-catenin due to GSK-3 inhibition, suggesting that the approach might be effective even in cancers with dysregulated β-catenin. These results suggest that GSK-3 inhibitors might be effectively combined with TRAIL for the treatment of pancreatic cancer.

Phylogenetic relationships among the family Ommastrephidae (Mollusca: Cephalopoda) inferred from two mitochondrial DNA gene sequences

Squids of the family Ommastrephidae are distributed worldwide, and the family includes many species of commercial importance. To investigate phylogenetic relationships among squid species of the family Ommastrephidae, partial nucleotide sequences of two mitochondrial gene loci (cytochrome c oxidase subunit I [1277bp] and 16S rRNA [443bp]) of 15 ommastrephid species and two outgroup species from the families Loliginidae and Enoploteuthidae were determined and used to construct parsimony and distance based phylogenetic trees. The molecular data provided several new phylogenetic inferences. The monophyletic status of three subfamilies (Illicinae, Todarodinae and Ommastrephinae) was well supported, although phylogenetic relationships between the subfamilies were not resolved. Inclusion of a problematic species, Ornithoteuthis volatilis, to Todarodinae was indicated. Within Todarodinae, the Japanese common squid Todarodes pacificus was observed to have much closer relationship to the species of the genus Nototodarus than to its congener (Todarodes filippovae). These results indicate that re-evaluation of several morphological key characters for ommastrephid taxonomy may be necessary.

Tenofovir selectively regulates production of inflammatory cytokines and shifts the IL-12/IL-10 balance in human primary cells

OBJECTIVES

In this study, we aimed to investigate the possible immune modulatory effects of HIV nucleoside reverse transcriptase inhibitors during secondary infections and inflammation, focusing on inflammatory cytokine responses and the interleukin (IL)-12/IL-10 balance.

METHODS

We investigated the in vitro effect of tenofovir and zidovudine (AZT) on production of proinflammatory cytokines in monocytes and human peripheral blood mononuclear cells (PBMCs). Stimulation panels included Toll-Like receptor (TLR) ligands; the inflammation mediator tumor necrosis factor-α; and the pathogens cytomegalovirus, Neisseria meningitides, Escherichia coli, and Streptococcus pneumoniae. Cytokine levels were measured using enzyme-linked immunosorbent assay and luminex technology. RNA levels were assessed using real-time polymerase chain reaction. Activity of mitogen-activated protein kinase and NF-κB signaling was evaluated using flow cytometry and multispectral imaging cytometry, respectively.

RESULTS

Tenofovir decreased and AZT increased both IL-8 and CCL3 production from monocytes after stimulation with TLR ligands, tumor necrosis factor-α, or live pathogens. Similarly, tenofovir decreased CCL3 levels in human PBMCs. Furthermore, tenofovir strongly decreased induction of IL-10 but increased levels of IL-12. AZT did not affect IL-12 or IL-10 levels. The observed drug-induced changes in cytokine production were independent from transcriptional regulation through the mitogen-activated protein kinase and nuclear factor kappa B pathways.

CONCLUSIONS

Our data suggest divergent effects of tenofovir and AZT on proinflammatory responses in monocytes (CCL3 and IL-8) and PBMCs (CCL3). Moreover, tenofovir shifts the IL-10/IL-12 balance after cell stimulation with TLR ligands or infection with live bacteria, thus suggesting that the choice of nucleoside reverse transcriptase inhibitor affects overall inflammation and early immune responses against secondary pathogens.

A phase I/II study of imatinib plus reinduction therapy for c-kit-positive relapsed/refractory acute myeloid leukemia: inhibition of Akt activation correlates with complete response

This phase I/II study evaluated imatinib as a c-kit inhibitor combined with mitoxantrone, etoposide and cytarabine therapy for patients with primary refractory or relapsed c-kit+ acute myeloid leukemia (AML). Imatinib was escalated through three dose levels in successive six patient cohorts. The combination was well tolerated up to 400 mg/day imatinib. Of 21 patients treated at this dose, 13 (62%) achieved complete response (CR), 7 (33%) were non-responders and one died during induction. The CR rate was 80% in patients with standard-risk karyotype versus 33% in patients with adverse karyotype. The CR rate for primary non-responders was 6/14 (43%) versus 7/7 (100%) for relapsed patients. AML blasts from peripheral blood were assayed for phosphorylated Akt (pAkt) and phosphorylated ERK (pERK) by flow cytometry before to and after imatinib dosing. Of eight patients achieving CR with reinduction, seven demonstrated marked (≥60%) pAkt inhibition with imatinib therapy. In contrast, all the six non-responders to reinduction demonstrated <60% pAkt inhibition (P=0.005). There was no correlation between pERK inhibition and response to therapy. These results indicate that lack of pAkt inhibition in vivo is associated with resistance to reinduction therapy using this regimen. Further studies using agents that are able to inhibit Akt more effectively are warranted.

Permanent genetic resources added to Molecular Ecology Resources Database 1 October 2010-30 November 2010

This article documents the addition of 277 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Ascochyta rabiei, Cambarellus chapalanus, Chionodraco hamatus, Coptis omeiensis, Cynoscion nebulosus, Daphnia magna, Gerbillus nigeriae, Isurus oxyrinchus, Lates calcarifer, Metacarcinus magister, Oplegnathus fasciatus, Pachycondyla verenae, Phaethon lepturus, Pimelodus grosskopfii, Rotylenchulus reniformis, Scomberomorus niphonius, Sepia esculenta, Terapon jarbua, Teratosphaeria cryptica and Thunnus obesus. These loci were cross-tested on the following species: Austropotamobius italicus, Cambarellus montezumae, Cambarellus puer, Cambarellus shufeldtii, Cambarellus texanus, Chionodraco myersi, Chionodraco rastrospinosus, Coptis chinensis, Coptis chinensis var. brevisepala, Coptis deltoidea, Coptis teeta, Orconectes virilis, Pacifastacus leniusculus, Pimelodus bochii, Procambarus clarkii, Pseudopimelodus bufonius, Rhamdia quelen, Sepia andreana, Sepiella maindroni, Thunnus alalunga, Thunnus albacares, Thunnus maccoyii, Thunnus orientalis, Thunnus thynnus and Thunnus tonggol.

Abstract 2529: The anti-malarial agent Mefloquine preferentially demonstrates pre-clinical activity in leukemia and myeloma cells through STAT1-induced reactive oxygen species production

Off patent drugs with previously unrecognized anti-leukemia activity can be rapidly repurposed for this new indication, given their prior safety and toxicity testing. By screening a group of anti-malarial compounds for anti-cancer activity, we identified mefloquine, a quinoline licensed in oral formulation for the treatment of malaria. As an anti-cancer agent, we demonstrated that mefloquine decreased the viability of 9/9 leukemia cell lines with an LD50 &lt;7.5 uM, and 9/9 myeloma cell lines with an LD50 &lt;5.0 uM. Furthermore, mefloquine demonstrated induced cell death in primary AML samples (n = 3; LD50 &lt;7.5 uM), but not normal peripheral blood stem cells. Given its in vitro activity, we evaluated the effects of oral mefloquine in mouse xenograft models of leukemia. Sublethally irradiated SCID mice were injected subcutaneously with OCI-AML2 or K562 human leukemia cells or MDAY-D2 murine leukemia cells, and treated with 50 mg/kg mefloquine, or vehicle alone by oral gavage. Oral mefloquine decreased tumor weight and volume in all 3 mouse models without toxicity.

Mechanistically, mefloquine induced reactive oxygen species (ROS) in leukemia cells at times preceding and concentrations associated with cell death. Blockade of ROS by N-acetyl-L-cysteine (NAC) abrogated mefloquine sensitivity, suggesting that mefloquine-mediated cell death in AML was ROS-dependent. To further understand the mechanism of mefloquine-mediated cytoxicity, whole genome gene expression oligonucleotide array analysis of AML cells treated with mefloquine was conducted. The gene expression pattern of cells treated with mefloquine strongly resembled gene signatures associated with activated Toll-like receptor and interferon response pathways. STAT1 and NF-κB, both downstream transcription factor components of TLR-IFN signaling, were activated, as were downstream targets IRF1, IRF7 and IL-8, at times that preceded mefloquine-induced cell death. Gene expression changes were validated by Q-RT-PCR, and are potential biomarkers of mefloquine activity in cells. This pathway appears functionally important for mefloquine-mediated cell death, as cell lines defective for STAT1 signaling components showed decreased cell death after mefloquine treatment. These lines also showed decreased ability to generate ROS in response to mefloquine treatment, suggesting that mefloquine-induced ROS was produced through a STAT1-dependent mechanism. Taken together, our data demonstrate that the anti-malarial mefloquine displays significant pre-clinical activity in leukemia and myeloma cells, likely through a STAT1-dependent induction of ROS that is triggered by activation of the TLR-IFN cytokine axis in cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2529.

Results from phase Ib studies of PX-12, a thioredoxin inhibitor in patients with advanced solid malignancies

2571

Background: PX-12, a small-molecule inhibitor of Thioredoxin-1 (Trx-1) stimulates apoptosis, down-regulates HIF- 1α, VEGF in animal models. High levels of Trx-1 have been linked to chemoresistance in lung cancers. The phase 2 dose of PX-12 was 226 mg/m2 given by 3-h infusion IV x 5 days, q 21d (Ramanathan RK et al. CCR 13; 2109; 2007). Two Phase 1b trials of PX-12 in patients with advanced solid tumors have been completed to determine the safety, tolerability and optimal biologic dose when delivered by prolonged infusion. Methods: PX-12 was administered as a 24-h infusion every q7- 14d starting at 150 mg/m2/day (n=18); or a 72-h infusion q 21d, starting at 300 mg/m2/day (n=14) using a portable delivery pump. Results: Both the 24- or 72-h infusion of PX-12 were well tolerated in patients at doses up to 400 mg/m2/day. Common grade 1/2 AE's included fatigue, taste alteration, and odor caused by expired drug metabolite. In the 24 h study the maximal dose evaluated was 450 mg/m2. No DLTs were observed in this study. Since no MTD was reached on 24-h infusion up to 450 mg/m2 dose level, additional higher doses were explored utilizing 72-h infusion. DLT in the 72-h study at the highest dose administered (500 mg/m2/day) included reversible hypoxia with or without pneumonitis. Best response was stable disease in 3 pts (SD): liver cancer and colon cancer (24-h infusion) and rectal cancer (72-h infusion). Pharmacodynamics (PD): PX- 12 lowered circulating Trx-1 levels in patients who had starting Trx-1 levels 3-fold greater than that of the normal population (5.4 ng/mL) including all three SD. Circulating VEGF and FGF-2 levels were also lowered over multiple courses of treatment in these patients. The pharmacokinetics of PX-12 showed a dose dependent increase of Cmax and no accumulation over multiple cycles following a 24 h infusion. Conclusions: Dosing at 400 mg/m2/day appears safe and tolerable as a 24–72-h infusion. Extending the infusion time to 72h appears to decrease the intensity of cough and odor compared to bolus 1–3 h infusion. The PD effect produced by PX-12 was apparent only in those patients with elevated plasma Trx-1 levels. Patients with elevated TRX-1 levels appear to have the best probability of having SD. Supported by ProlX Pharmaceuticals/Oncothyreon through an award from the NCI.

[Table: see text]

Preliminary analysis of length and GC content variation in the ribosomal first internal transcribed spacer (ITS1) of marine animals

Length and guanine-cytosine (GC) content of the ribosomal first internal transcribed spacer (ITS1) were compared across a wide variety of marine animal species, and its phylogenetic utility was investigated. From a total of 773 individuals representing 599 species, we only failed to amplify the ITS1 sequence from 87 individuals by polymerase chain reaction with universal ITS1 primers. No species was found to have an ITS1 region shorter than 100 bp. In general, the ITS1 sequences of vertebrates were longer (318 to 2,318 bp) and richer in GC content (56.8% to 78%) than those of invertebrates (117 to 1,613 bp and 35.8% to 71.3%, respectively). Specifically, gelatinous animals (Cnidaria and Ctenophora) were observed to have short ITS1 sequences (118 to 422 bp) with lower GC content (35.8% to 61.7%) than the other animal taxa. Mollusca and Crustacea were diverse groups with respect to ITS1 length, ranging from 108 to 1,118 and 182 to 1,613 bp, respectively. No universal relationship between length and GC content was observed. Our data indicated that ITS1 has a limited utility for phylogenetic analysis as obtaining confident sequence alignment was often impossible between different genera of the same family and even between congeneric species.

Lack of correlation of the health assessment questionnaire disability index with lung parameters in systemic sclerosis associated pulmonary arterial hypertension

OBJECTIVE

Pulmonary arterial hypertension (PAH) affects the quality of life (QoL) and the ability to perform the activities of daily living (ADLs) in patients with systemic sclerosis (SSc). We determined whether the Health Assessment Questionnaire-Disability Index (HAQ-DI), a self-assessment measure of function, correlates with a patient's PAH status in a population of SSc patients with PAH.

METHODS

Forty-one patients from one centre with systemic scleroderma, dyspnea and PAH were included. All patients filled in a HAQ-DI, and underwent evaluation with pulmonary function tests (PFTs), 6-minute walk distance (6MWD), degree of dyspnea (Borg dyspnea index), NYHA functional class, and expert PAH physician global assessment every 6 months. Change in HAQ DI was studied to determine relationship to changes in PAH.

RESULTS

The HAQ-DI scores had no significant correlation with PAH, including NYHA functional class (r=0.38, p=0.39), Borg dyspnea index (r=0.60, p=0.37), 6MWD (r=-0.04, p=0.86), % predicted DLCO (r=0.31, p=0.25), % predicted FVC (r=0.02, p=0.93), and expert PAH physician global assessment (r=0.06, p=0.97).

CONCLUSION

HAQ-DI is not an adequate measure of PAH status in SSc patients with PAH. Although PAH causes severe morbidity and death, changes in PAH severity were not reflected in an overall functional status change as assessed by the HAQ-DI. Thus, HAQ-DI changes do not reflect PAH status in SSc.

Flow cytometric measurement of intracellular pH

A number of fundamentally important biological processes, such as cell signaling and the initiation of mitosis, are accompanied by a change in intracellular pH. Flow cytometric measurement of pH is a generally straightforward procedure that can be done with any instrument equipped with a 488-nm argon laser. The overall approach is similar to that for calcium: generation of a calibration curve by imparting known changes in pH and interpolation of the test sample pH. This unit presents the traditional calibration method using high-potassium buffers and the proton ionophore nigericin and a more recently developed technique, the pseudo null method, which involves resuspension of cells in defined mixtures of weak acids and weak bases.

Pharmacodynamic monitoring of molecular-targeted agents in the peripheral blood of leukemia patients using flow cytometry

The introduction of specific, molecular-targeted drugs is radically changing cancer treatment. Pharmacodynamics, which measures drug effects on the host, is key during early-phase clinical trials of novel agents to determine the relations between drug dose and target inhibition as well as measure the downstream effects of target inhibition on the cancer. In this article, we describe the application of flow cytometry to the pharmacodynamic monitoring of molecular-targeted agents in leukemia patients. The methods are based on current clinical flow-cytometry applications, with the addition of phosphospecific antibodies to measure the activation states of intracellular signaling elements and the introduction of techniques that maintain drug-target equilibrium during sample preparation. Using this approach, we successfully showed dose-dependent inhibition of c-Kit during a phase I clinical trial treating acute leukemia patients with the novel agent sorafenib. Further refinements identify considerable interpatient variation in signaling activity within leukemic blast populations, suggesting that an individualized approach to treatment based on flow cytometric monitoring might be advantageous. Improvements in sample turnaround offer the potential to introduce real-time pharmacodynamic monitoring during early-phase clinical trials.